Executives were ebullient at ceremonies for the first formal delivery Wednesday, to Air New Zealand, of a 787-9 painted a striking black and white.

In fact, many of them seemed resigned to looking at the battery and oth er problems of the earlier 787-8 as a steep learning curve that has finally culminated in a much more refined, and larger, 787-9.

“We took all the lessons we learned on the 8 and incorporated them on the 9,” said Mark Jenks, vice president, 787 Airplane Development, in a brief interview.

“The first dash 9 is going to enter into service at the level the dash 8 already has achieved,” Jenks said. “In some cases we’ve put things on the 9 that are fundamentally more reliable and will ultimately be better than we’ve seen on the dash 8.”

But all that seemed forgotten Wednesday, as media people from New Zealand, China and the United States swarmed the Everett Delivery Center and vied for chances to speak with Boeing and Air New Zealand officials there.

Some of the improvements to the 787-9 include perfected software, a better wing-to-body join, and even a new process of building the aircraft’s hull ribs in one piece instead of the two used for the earlier 787-8, Jenks said.

“We’ve been able to improve the manufacturing process where we’ve been able to do that in a single piece,” he said. “When you do that throughout the airplane, saving a little weight, it really makes a difference.”

Jeff Klemann, vice president of 787-9 delivery operations, said in another interview that flight tests before delivery are now happening almost as smoothly as with the 777, which has been in production since the late ‘90s.

“The 787 is zeroing in the 777, and you know how long the 777 has been flying,” he said. “They (787s) are flying much better, and they’re almost comparable to the 777.”

The 787-9 itself is incrementally more spacious than the preceding smaller model, reflecting the extra 20 feet of fuselage.

The interior was all black and white, which one observer described as a Goth look, although tinged purple by the model’s adjustable inside lights.

One compromise Air New Zealand has had to make, reflecting the long flight times to New Zealand, is packing in extra galley space — right at the center of the aircraft.

That means when passengers board the airplane, rather than entering into the spacious foyer envisioned by Boeing designers they instead walk into the kitchen, like entering a home from the back door.